1,721,002 research outputs found
ANALYSIS OF NEUROMUSCULAR JUNCTIONS AND EFFECTS OF NANDROLONE ADMINISTRATION IN A MOUSE MODEL FOR ALS
Full text linkSeveral lines of evidence indicate that neuromuscular junction (NMJ) destruction and disassembly is an early phenomenon in the amyotrophic lateral sclerosis (ALS) neurodegenerative disease. Here we analyzed by confocal and electron microscopy the NMJ structure in the diaphragm of Superoxide dismutase (SOD)1 G93A mice at symptom onset and we compared these observation with animals sacrificed at the pathological end stage. In young transgenic mice, which provide a model for familial ALS, the present findings showed marked denervation both in the diaphragm and in the gastrocnemius, which partially spares soleus muscle. At the clinical end stage even the soleus is slight denervated, but less severely than other muscles. In addition, the size of the synaptic vesicle (SV) pool was found reduced and alterations of mitochondria were observed in approximately 40% of the remaining presynaptic terminals. Treatment of SOD1 G93A mice with the anabolic steroid nandrolone during the presymptomatic stage preserved the diaphragm muscle mass and features indicative of synaptic activity, represented by the number of vesicles docked within 200 nm from the presynaptic membrane and area of acetylcholine receptor clusters. Furthermore, structural preservation of mitochondria was documented in presynaptic terminals, but innervation of diaphragm muscle fibers was only slightly increased in nandrolone-treated SOD1-mutant mice. Altogether the results point out and define fine structural alterations of diaphragm NMJs in the murine model of familial ALS at symptom onset, and indicate that nandrolone may prevent or delay structural alterations in NMJ mitochondria and stimulate presynaptic activity but does not prevent muscle denervation in the disease
Neuromuscular Junction Dismantling in Amyotrophic Lateral Sclerosis
Full text linkNeuromuscular junction assembly and plasticity during embryonic, postnatal, and adult life are tightly regulated by the continuous cross-talk among motor nerve endings, muscle fibers, and glial cells. Altered communications among these components is thought to be responsible for the physiological age-related changes at this synapse and possibly for its destruction in pathological states. Neuromuscular junction dismantling plays a crucial role in the onset of Amyotrophic Lateral Sclerosis (ALS). ALS is characterized by the degeneration and death of motor neurons leading to skeletal muscle denervation, atrophy and, most often, death of the patient within five years from diagnosis. ALS is a non-cell autonomous disease as, besides motor neuron degeneration, glial cells, and possibly muscle fibers, play a role in its onset and progression. Here, we will review the recent literature regarding the mechanisms leading to neuromuscular junction disassembly and muscle denervation focusing on the role of the three players of this peripheral tripartite synapse
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Alterazioni fonetiche in soggetti con malocclusioni dentali e/o ostruzione respiratoria nasale.
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Valutazione della specificità di substrato delle lipasi da Candida rugosa e Rhizomucor miehei
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